The 3D numerical simulation model of deep hard-rock deposit in Kaiyang Phosphate Mine of Guiyang was established based on the practical engineering using 3DEC numerical simulation software. The distribution characteri...The 3D numerical simulation model of deep hard-rock deposit in Kaiyang Phosphate Mine of Guiyang was established based on the practical engineering using 3DEC numerical simulation software. The distribution characteristics of displacement fields and plastic zones of the orebody were simulated in three different excavation cases, including the case of excavation artificial inducted roadway in the orebody, the case of horizontal or vertical excavation direction and the case of the upward or downward excavation order. The simulation results indicate that the plastic zone and displacement field of surrounding rock around the inducted roadway are continuously increasing with the increase of the exposure time after digging an artificial inducted roadway in the orebody. Thus the raw rock ore becomes easier to be fragmented, which provides advantageous conditions for roadheader to cut high stress hard-rock. It is worthy noting that there is a large difference in effective utilization of deep ground pressure between horizontal and vertical excavation directions. The later can produce larger deformation and fracture zone than the former on the rock mass around the deduced roadway, which means that the later may utilize the high ground pressure more effectively to break hard-rock. And the obtained results also show that upward excavation order is more helpful for ground pressure to break rock than downward excavation order.展开更多
冰载荷是海上风机在寒区安全运行的重要影响因素之一,由其引发的冰激振动给风机结构带来了严重的危害.本文通过离散元(discrete element method, DEM)--有限元(finite element method, FEM)耦合方法建立了寒区单桩式风机结构的冰激振动...冰载荷是海上风机在寒区安全运行的重要影响因素之一,由其引发的冰激振动给风机结构带来了严重的危害.本文通过离散元(discrete element method, DEM)--有限元(finite element method, FEM)耦合方法建立了寒区单桩式风机结构的冰激振动模型.采用具有粘结-破碎性能的球体离散单元描述平整海冰损伤破坏行为,采用梁单元和三角形平板壳单元构造带有抗冰锥体的单桩式风机有限元模型.采用DEM-FEM耦合方法模拟不同冰速、冰厚条件下单桩式风机与平整冰相互作用过程,并且与IEC规范和ISO标准经验公式对比验证该耦合模型计算冰载荷的准确性.对比风机塔筒顶端和基础顶端的位移和加速度响应时程,定性地给出风机结构不同部位振动响应行为差异性.风机不同部位动力特性差异原因为风机结构独特结构特点:下部为大刚度桩基和上部为高柔度塔筒,使其动力特征表现为主从式结构特性."主-从式结构"特征使得结构在复杂的冰载荷作用下,风机塔筒(子结构)和桩基(主结构)表现为不同的响应行为,风机不同部位振动周期和加速度谱两者出现差异.本文研究成果为海上风机抗冰设计和疲劳分析提供了有益参考.展开更多
基金Projects (50934006, 10872218) supported by the National Natural Science Foundation of ChinaProject (2010CB732004) supported by the National Basic Research Program of China
文摘The 3D numerical simulation model of deep hard-rock deposit in Kaiyang Phosphate Mine of Guiyang was established based on the practical engineering using 3DEC numerical simulation software. The distribution characteristics of displacement fields and plastic zones of the orebody were simulated in three different excavation cases, including the case of excavation artificial inducted roadway in the orebody, the case of horizontal or vertical excavation direction and the case of the upward or downward excavation order. The simulation results indicate that the plastic zone and displacement field of surrounding rock around the inducted roadway are continuously increasing with the increase of the exposure time after digging an artificial inducted roadway in the orebody. Thus the raw rock ore becomes easier to be fragmented, which provides advantageous conditions for roadheader to cut high stress hard-rock. It is worthy noting that there is a large difference in effective utilization of deep ground pressure between horizontal and vertical excavation directions. The later can produce larger deformation and fracture zone than the former on the rock mass around the deduced roadway, which means that the later may utilize the high ground pressure more effectively to break hard-rock. And the obtained results also show that upward excavation order is more helpful for ground pressure to break rock than downward excavation order.
文摘冰载荷是海上风机在寒区安全运行的重要影响因素之一,由其引发的冰激振动给风机结构带来了严重的危害.本文通过离散元(discrete element method, DEM)--有限元(finite element method, FEM)耦合方法建立了寒区单桩式风机结构的冰激振动模型.采用具有粘结-破碎性能的球体离散单元描述平整海冰损伤破坏行为,采用梁单元和三角形平板壳单元构造带有抗冰锥体的单桩式风机有限元模型.采用DEM-FEM耦合方法模拟不同冰速、冰厚条件下单桩式风机与平整冰相互作用过程,并且与IEC规范和ISO标准经验公式对比验证该耦合模型计算冰载荷的准确性.对比风机塔筒顶端和基础顶端的位移和加速度响应时程,定性地给出风机结构不同部位振动响应行为差异性.风机不同部位动力特性差异原因为风机结构独特结构特点:下部为大刚度桩基和上部为高柔度塔筒,使其动力特征表现为主从式结构特性."主-从式结构"特征使得结构在复杂的冰载荷作用下,风机塔筒(子结构)和桩基(主结构)表现为不同的响应行为,风机不同部位振动周期和加速度谱两者出现差异.本文研究成果为海上风机抗冰设计和疲劳分析提供了有益参考.
